The electronic spectroscopy of jet-cooled difluorocarbene (CF{sub 2}): The missing {ital {tilde A}}-state stretching frequencies

Journal Article · Fri Sep 15 04:00:00 EDT 1995 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.470728· OSTI ID:122960

Cameron, M R; Kable, S H; Bacskay, G B ^[1]

---

1. School of Chemistry, University of Sydney, Sydney, New South Wales, 2006 (Australia)

The {ital {tilde A}}({sup 1}{ital B}{sub 1}){l_arrow}{ital {tilde X}}({sup 1}{ital A}{sub 1}) electronic transition of difluorocarbene (CF{sub 2}) has been studied by laser-induced fluorescence spectroscopy in a supersonic free jet and by {ital ab} {ital initio} theoretical methods. The radical was formed by pyrolysis of C{sub 2}F{sub 4} at {similar_to}1000 {degree}C with a heating chamber at the tip of the nozzle just prior to the gas expansion. Fairly complete rotational cooling, but incomplete vibrational cooling allowed the identification of several new hot band transitions. {ital Ab} {ital initio} calculations for the {ital {tilde X}}({sup 1}{ital A}{sub 1}), {ital {tilde a}}({sup 3}{ital B}{sub 1}), and {ital {tilde A}}({sup 1}{ital B}{sub 1}) electronic states were performed using the CASSCF method in conjunction with Dunning`s cc-pVTZ basis set, as well as two smaller sets. The calculations allow us to distinguish between several possible assignments of the observed transitions, and hence determine the vibrational frequencies of the two previously unassigned {ital {tilde A}}-state stretching frequencies: {nu}{sub 3}{sup {prime}}=1180{plus_minus}2 cm{sup {minus}1} and {nu}{sub 1}{sup {prime}}=1011{plus_minus}2 cm{sup {minus}1}. The ordering of these modes is different from that in the ground state ({nu}{sub 1}{sup {double_prime}}{gt}{nu}{sub 3}{sup {double_prime}}) and mechanisms for the switching are discussed.

• Research Organization: Oak Ridge National Laboratory
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 122960
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 11 Vol. 103; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
BOND LENGTHS
CARBENES
CARBON FLUORIDES
ENERGY-LEVEL TRANSITIONS
INFRARED RADIATION
LASER SPECTROSCOPY
MOLECULAR STRUCTURE
OZONIZATION
PHOTOLYSIS
VIBRATIONAL STATES